Bath for electroplating bright tin or tin-lead alloys and method thereof

Abstract

This invention relates to alkyl and alkanol sulfonic acid plating baths and to methods for plating tin and tin-lead alloys. It also relates to low foaming wetting systems based on low to moderate foaming surfactants and soluble, non-silicon containing defoamers, and to low volatility brightener systems.

What is claimed is: 
     
       1. A tin or tin-lead alloy plating bath for the electrodeposition of bright plates which comprises: A. a plating bath containing a bath soluble alkane or alkanol sulfonic acid;   B. tin alkane or alkanol sulfonate or both tin and lead alkane or alkanol sulfonate;   C. a first low volatility brightening agent selected from the group consisting of dialdehyde precursors capable of undergoing acid hydrolysis under plating bath conditions, selected from the group consisting of a substituted dihydropyran represented by the following two formulas: ##STR27##  wherein R 1 , R 2 , R 3 , and R 4  represent hydrogen or a C 1-5  alkyl group; x is an integer from 0 to 5; and     D. a second low volatility brightening agent selected from the group consisting of (a) aromatic aldehydes and substituted aromatic aldehydes, with the exception of benzaldehyde;   (b) aromatic ketones or substituted aromatic ketones; and   (c) carboxaldehydes of heterocyclic rings or substituted heterocyclic rings.     
     
     
       2. A tin or tin-lead alloy plating bath for the electrodeposition of bright plates which comprises: A. a plating bath containing a bath soluble alkane or alkanol sulfonic acid;   B. tin alkane or alkanol sulfonate or both tin and lead alkane or alkanol sulfonate;   C. a first low volatility brightening agent selected from the group consisting of dialdehyde precursors capable of undergoing acid hydrolysis under plating bath conditions, selected from the group consisting of substituted dihydrofurans represented by the formulas ##STR28##  wherein R 1 , R 2 , R 3  and R 4  represent hydrogen or a C 1-5  alkyl group; and     D. a second low volatility brightening agent selected from the group consisting of (a) aromatic aldehydes and substituted aromatic aldehydes, with the exception of benzaldehyde;   (b) aromatic ketones or substituted aromatic ketones; and   (c) carboxaldehydes of heterocyclic rings or substituted heterocyclic rings.     
     
     
       3. A tin or tin-lead alloy plating bath for the electrodeposition of bright plates which comprises: A. a plating bath containing a bath soluble alkane or alkanol sulfonic acid;   B. tin alkane or alkanol sulfonate or both tin and lead alkane or alkanol sulfonate;   C. at least one low volatility brightening agent selected from the group consisting of a dialdehyde precursor capable of undergoing acid hydrolysis selected from the group consisting of substituted tetrahydrofuran represented by the formula ##STR29##  wherein R 1 , R 2 , R 3  and R 4  represent hydrogen or a C 1-5  alkyl group; and       D. at least one second low volatility brightening agent selected from the group consisting of (a) aromatic aldehydes and substituted aromatic aldehydes, with the exception of benzaldehyde;   (b) aromatic ketones or substituted aromatic ketones; and   (c) carboxaldehydes of heterocyclic rings or substituted heterocyclic rings.     
     
     
       4. A tin or tin-lead alloy plating bath for the electrodeposition of bright plates which comprises: A. a plating bath containing a bath soluble alkane or alkanol sulfonic acid;   B. tin alkane or alkanol sulfonate or both tin and lead alkane or alkanol sulfonate;   C. at least one low volatility brightening agent selected from the group consisting of a dialdehyde precursor capable of undergoing acid hydrolysis selected from the group consisting of acetals of dialdehyde represented by the formula ##STR30##  wherein R 1 , R 2 , R 3 , R 4 , R 5  and R 6  represent hydrogen or a C 1-5  alkyl group; n is an integer from 1 to 10; and     D. at least one second low volatility brightening agent selected from the group consisting of (a) aromatic aldehydes and substituted aromatic aldehydes, with the exception of benzaldehyde;   (b) aromatic ketones or substituted aromatic ketones; and   (c) carboxaldehydes of heterocyclic rings or substituted heterocyclic rings.     
     
     
       5. A tin or tin-lead alloy plating bath for the electrodeposition of bright plates which comprises: A. a plating bath containing a bath soluble alkane or alkanol sulfonic acid;   B. tin alkane or alkanol sulfonate or both tin and lead alkane or alkanol sulfonate;   C. at least one low volatility brightening agent selected from the group consisting of a dialdehyde precursor capable of undergoing acid hydrolysis selected from the group consisting of hydroxysulfonates represented by the formula ##STR31##  wherein R 1  and R 2   represent hydrogen, hydroxy-, or a C 1-5  alkyl group; M is an alkali metal, x is an integer from 0 to 10; and     D. at least one second low volatility brightening agent selected from the group consisting of (a) aromatic aldehydes and substituted aromatic aldehydes, with the exception of benzaldehyde;   (b) aromatic ketones or substituted aromatic ketones; and   (c) carboxaldehydes of heterocyclic rings or substituted heterocyclic rings.     
     
     
       6. A tin or tin-lead alloy plating bath for the electrodeposition of bright plate which consists essentially of: A. a plating bath containing a bath soluble alkane or alkanol sulfonic acid;   B. tin alkane or alkanol sulfonate or both tin and lead alkane or alkanol sulfonate;   C. a first low volatility brightening agent selected from the group consisting of (a) a dialdehyde precursor capable of undergoing acid hydrolysis selected from the group consisting of i. a substituted dihydropyran represented by the following two formulas: ##STR32##  wherein R 1 , R 2 , R 3 , and R 4  represent hydrogen or a C 1-5  alkyl group; x is an integer from 0 to 5; and/or   ii. a substituted dihydrofuran represented by the formulas ##STR33##  wherein R 1 , R 2 , R 3  and R 4  represent hydrogen or a C 1-5  alkyl group; and/or   iii. a substituted tetrahydrofuran represented by the formula ##STR34##  wherein R 1 , R 2 , R 3  and R 4  represent hydrogen or a C 1-5  alkyl group; and/or   iv. an acetal of dialdehyde represented by the formula ##STR35##  wherein R 1 , R 2 , R 3 , R 4 , R 5  and R 6  represent hydrogen or a C 1-5  alkyl group; x is an integer from 1 to 10; and/or   v. a hydroxysulfonate represented by the formula ##STR36##  wherein R 1  and R 2  represent hydrogen, hydroxy-, or a C 1-5  alkyl group; M is an alkali metal, x is an integer from 0 to 10;       D. a second low volatility brightening agent selected from the group consisting of (a) aromatic aldehydes and substituted aromatic aldehydes, excluding benzaldehyde; and/or   (b) aromatic ketones or substituted aromatic ketones; and/or   (c) carboxaldehydes of heterocyclic rings or substituted heterocyclic rings; and     E. a surfactant selected from the group consisting of: (a) a nonionic surfactant selected from the group represented by the formula ##STR37##  wherein R 1  and R 2  represent hydrogen or --CH 3  ; R 3 , R 4  and R 5  represent H, a C 1-20  alkyl, benzyl, and/or a styryl group; x and y are integers from 1-30; and/or   (b) a nonionic surfactant that is a block copolymer of ethylene and propylene oxide selected from the group represented by the formula ##STR38##  wherein A represents a halogen, --OH, or --OR, where R is a C 1-15  group; x, y, and z are integers from 1 to 100; and/or   (c) a nonionic surfactant that is a block copolymer of ethylene and propylene oxide selected from the group represented by the formula ##STR39##  wherein A represents a halogen, --OH, or --OR, where R is a C 1-15  group; x, y, and z are integers from 1 to 100;     F. a non-silicon defoaming agent selected from the group consisting of: (a) a polypropylene oxide or nonionic surfactant from the group represented by the formula ##STR40##  wherein A represents a halogen, --OH, or --OR, where R is a C 1-15  alkyl group; x, y, z are integers from 1 to 100; with the condition that no more than 10% of the compound is polyethylene oxide; and/or   (b) a polyproplyene oxide or nonionic surfactant from the group represented by the formula ##STR41##  wherein A represents a halogen, --OH, or --OR, where R is a C 1-15  alkyl group; x, y, z are integers from 1 to 100 with the condition that no more than 10% of the compound is polyethylene oxide; and/or   (c) an aliphatic alcohol, represented by the formula   R--OH        wherein R is a C 5-30  alkyl group; and/or   (d) an ethoxylated alkyl phenol from the group represented by the formula ##STR42##  wherein R 1 , R 2  and R 3  represent hydrogen or C 1-16  alkyl groups with the condition that there is at least one alkyl group; x is an integer from 1-5 and     G. antioxidants selected from the group consisting of 1-phenyl-3-pyrazolidinone, resorcinol, catechol, and hydroquinone sulfonate.   
     
     
       7. The plating bath according to claim 1, 2, 3, 4, 5, or 6, in which the electrolyte consists of alkane and alkanol sulfonic acids represented by the general formulas   RCH.sub.2 SO.sub.3 H     wherein R represents a C 1-6  alkyl group, and     HO--RSO.sub.3 H     wherein R represents a C 1-6  alkylene group.   
     
     
       8. The plating bath according to claim 1, 2, 3, 4, 5, or 6, in which the alkane or alkanol sulfonic acid electrolyte is used in concentrations ranging from to 25 percent acid. 
     
     
       9. The plating bath according to claim 1, 2, 3, 4, 5, or 6, in which the tin is supplied as stannous alkane sulfonate or stannous alkanol sulfonate: Sn(O 3  SR) 2  or Sn(O 3  S--R--OH) 2 , respectively, where total tin metal concentration ranges form 10 to 100 grams per liter. 
     
     
       10. The plating bath according to claim 6, in which the tin is supplied as a tin alkane or alkanol sulfonate or a mixture thereof at a concentration ranging from about 2 to 25 percent, and the lead is supplied as a plumbous alkane sulfonate represented by the formulae:   Pb(O.sub.3 SR).sub.2 or Pb(O.sub.3 S-R-OH).sub.2     wherein R represents a C 1-12  alkyl group and where the total tin metal concentration ranges and the total lead metal concentration ranges from about 0.25 to about 50 grams per liter.   
     
     
       11. The plating bath according to claim 6, in which the defoamer is used in concentrations of 0.01 to about 30 grams per liter. 
     
     
       12. The plating bath according to claim 1, 2, 3, 4, 5, or 6, in which the dialdehyde brightener or its precursor is used in concentrations of 0.1 to 20 grams per liter. 
     
     
       13. The plating bath according to claim 1, 2, 3, 4, 5, or 6, in which the aromatic aldehyde and/or the aromatic ketone and/or the carboxaldehyde substituted heterocyclic ring is used in concentrations of from about 0.005 to about 0.5 grams per liter. 
     
     
       14. The plating bath according to claim 6, in which the antioxidant is used in concentrations of from about 0.1 to about 0.8 grams per liter. 
     
     
       15. A process for producing a bright electroplate of tin or tin-lead comprising contacting an electroplatable object, with an electroplating bath as defined in claim 1, 2, 3, 4, 5, or 6. 
     
     
       16. The process of claim 15, wherein bath electrolytes are selected from bath soluble alkane or alkanol sulfonic acids. 
     
     
       17. The process of claim 15, wherein the source of tin or tin and lead is alkane or alkanol sulfonate containing each of the metals in the plus two oxidation state. 
     
     
       18. The process of claim 15, wherein the plating bath contains at least one of the low to moderate foaming surfactants of claim 7 in a concentration between about 1 and about 15 grams per liter. 
     
     
       19. The process of claim 15, wherein the plating bath contains at least one of the nonsilicon containing defoamers of claim 7. 
     
     
       20. The process of claim 15, wherein the plating bath contains an aliphatic dialdehyde, substituted aliphatic dialdehyde, or a precursor hydrolyzable to an aliphatic dialdehyde or a substituted aliphatic dialdehyde in an acidic plating bath. 
     
     
       21. The process of claim 15, wherein the plating bath contains a low volatility brightening agent selected from the group consisting of: (a) aromatic aldehydes and substituted aromatic aldehydes and/or their acid hydrolyzable precursors; and/or   (b) aromatic ketones or substituted aromatic ketones; and/or   (c) carboxaldehydes of heterocyclic rings or substituted heterocyclic rings.   
     
     
       22. The process of claim 15, wherein the plating bath contains an antioxidant selected from resorcinol, catechol, hydroquinone sulfonate, or 1-phenyl-3-pyrozolidinone. 
     
     
       23. The process of claim 15, wherein said process results in a semi-bright finish. 
     
     
       24. The process of claim 15, wherein said process results in a mirror-bright finish. 
     
     
       25. A tin or tin-lead alloy plating bath for the electrodeposition of bright plates which comprises: A. a plating bath containing a bath soluble alkane or alkanol sulfonic acid;   B. tin alkane or alkanol sulfonate or both tin and lead alkane or alkanol sulfonate;   C. a brightening agent selected from the group consisting of a non-volatile brightness selected from the group of i. a substituted dihydropyran represented by the following two formulae: ##STR43##  wherein R 1 , R 2 , R 3 , and R 4  represent hydrogen or a C 1-5  alkyl group; x is an integer from 0 to 5; and/or   ii. a substituted dihydrofuran represented by the formulae: ##STR44##  wherein R 1  R 2 , R 3  and R 4  represent hydrogen or a C 1-5  alkyl group; and/or   iii. a substituted tetrahydrofuran represented by the formula ##STR45##  wherein R 1 , R 2 , R 3  and R 4  represent hydrogen or a C 1-5  alkyl group; and/or   iv. an acetal of dialdehyde represented by the formula ##STR46##  wherein R 1 , R 2 , R 3 , R 4 , R 5  and R 6  represent hydrogen or a C 1-5  alkyl group; x is an integer from 1 to 10; and/or   v. a hydroxysulfonate represented by the formula ##STR47##  wherein R 1  and R 2  represent hydrogen, hydroxyl, or a C 1-5  alkyl group; M is an alkali metal, x is an integer from 0 to 10;     D. second low volatility brightening agent selected from the group consisting of (a) aromatic aldehydes and substituted aromatic aldehydes, excluding benzaldehyde; and/or   (b) aromatic ketones or substituted aromatic ketones; and/or   (c) carboxaldehydes of heterocyclic rings or substituted heterocyclic rings; and     E. a surfactant selected from the group consisting of: (a) a nonionic surfactant selected from the group represented by the formula ##STR48##  wherein R 1  and R 2  represent hydrogen or --CH 3  ; R 3 , R 4  and R 5  represent H, a C 1-20  alkyl, benzyl, and/or a styryl group; x and y are integers from 1-30; and/or   (b) a nonionic surfactant that is a block copolymer of ethylene and propylene oxide selected from the group represented by the formula ##STR49##  wherein A represents a halogen, --OH, or --OR, where R is a c 1-15  group; x, y, an dz are integers from 1 to 100; and/or   (c) a nonionic surfactant that is a block copolymer of ethylene and propylene oxide selected from the group represented by the formula ##STR50##  wherein A represents a halogen, --OH, or --OR, where R is a C 1-15  group; x, y, and z are integers from 1 to 100;     F. a non-silicon defoaming agent selected from the group consisting of: (a) a polypropylene oxide or nonionic surfactant from the group represented by the formula ##STR51##  wherein A represents a halogen, --OH, or --OR, where R is a C 1-15  alkyl group; x, y, z are integers from 1 to 100; with the condition that no more than 10% of the compound is polyethylene oxide; and/or   (b) a polypropylene oxide or nonionic surfactant from the group represented by the formula ##STR52##  wherein A represents a halogen, --OH, or --OR, where R is a C 1-15  alkyl group; x, y, z are integers from 1 to 100 with the condition that no more than 10% of the compound is polyethylene oxide; and/or   (c) analiphatic alcohol, represented by the formula,   R--OH        wherein R is a C 5-30  alkyl group; and/or   (d) an ethoxylated alkyl phenol from the group represented by the formula ##STR53##  wherein R 1 , R 2  and R 3  represent hydrogen or C 1-16  alkyl groups with the condition that there is at least one alkyl group; x is an integer from 1-5; and     G. antioxidants selected from the group consisting of 1-phenyl-3-pyrazolidinone, resorcinol, catechol, and hydroquinone sulfonate.   
     
     
       26. A tin or tin-led alloy plating bath according to claim 25 for the electrodeposition of bright plates which consists essentially of: A. a plating bath containing a bath soluble alkane or alkanol sulfonic acid;   B. tin alkane or alkanol sulfonate or both tin and lead alkane or alkanol sulfonate;   C. a first low volatility brightening agent selected from the group consisting of dialdehyde precursors capable of undergoing acid hydrolysis under plating bath conditions, selected from the group consisting of a substituted dihydropyran represented by the following two formulae: ##STR54##  wherein R 1 , R 2 , R 3 , and R 4  represent hydrogen or a C 1-5  alkyl group; x is an integer from 0 to 5; and     D. a second low volatility brightening agent selected from the group consisting of (a) aromatic aldehydes and substituted aromatic aldehydes, with the exception of benzaldehyde;   (b) aromatic ketones or substituted aromatic ketones; and   (c) carboxaldehydes of heterocyclic rings or substituted heterocyclic rings.     
     
     
       27. A tin or tin-lead alloy plating bath according to claim 25 for the electrodeposition of bright plates which consists essentially of: A. a plating bath containing a bath soluble alkane or alkanol sulfonic acid;   B. tin alkane or alkanol sulfonate or both tin and lead alkane or alkanol sulfonate;   C. a first low volatility brightening agent selected from the group consisting of dialdehyde precursors capable of undergoing acid hydrolysis under plating bath conditions, selected from the group consisting of substituted dihydrofurans represented by the formulae: ##STR55##  wherein R 1 , R 2 , R 3  and R 4  represent hydrogen or a C 1-5  alkyl group; and     D. a second low volatility brightening agent selected from the group consisting of (a) aromatic aldehydes and substituted aromatic aldehydes, with the exception of benzaldehyde;   (b) aromatic ketones or substituted aromatic ketones; and   (c) carboxaldehydes of heterocyclic rings or substituted heterocyclic rings.     
     
     
       28. A tin or tin-lead alloy plating bath according to claim 25 for the electrodeposition of bright plates which consists essentially of: A. a plating bath containing a bath soluble alkane or alkanol sulfonic acid;   B. tin alkane or alkanol sulfonate or both tin and lead alkane or alkanol sulfonate;   C. at least one low volatility brightening agent selected from the group consisting of a dialdehyde precursor capable of undergoing acid hydrolysis selected from the group consisting of substituted tetrahydrofurans represented by the formula ##STR56##  wherein R 1 , R 2 , R 3  and R 4  represent hydrogen or a C 1-5  alkyl group; and       D. at least one second low volatility brightening agent selected from the group consisting of (a) aromatic aldehydes and substituted aromatic aldehydes, with the exception of benzaldehyde;   (b) aromatic ketones or substituted aromatic ketones; and   (c) carboxaldehydes of heterocyclic rings or substituted heterocyclic rings.     
     
     
       29. A tin or tin-lead alloy plating bath of claim 25 for the electrodeposition of bright plates which consists essentially of: A. a plating bath containing a bath soluble alkane or alkanol sulfonic acid;   B. tin alkane or alkanol sulfonate or both tin and lead alkane or alkanol sulfonate;   C. at least one low volatility brightening agent selected from the group consisting of a dialdehyde precursor capable of undergoing acid hydrolysis selected from the group consisting of acetals of dialdehyde represented by the formula ##STR57##  wherein R 1 , R 2 , R 3 , R 4 , R 5  and R 6  represent hydrogen or a C 1-5  alkyl group; x is an integer from 1 to 10; and     D. at least one second low volatility brightening agent selected from the group consisting of (a) aromatic aldehydes and substituted aromatic aldehydes, with the exception of benzaldehyde;   (b) aromatic ketones or substituted aromatic ketones; and   (c) carboxaldehydes of heterocyclic rings or substituted heterocyclic rings.     
     
     
       30. A tin or tin-lead alloy plating bath of claim 25 for the electrodeposition of bright plates which consists essentially of: A. a plating bath containing a bath soluble alkane or alkanol sulfonic acid;   B. tin alkane or alkanol sulfonate or both tin and lead alkane or alkanol sulfonate;   C. at least one low volatility brightening agent selected from the group consisting of a dialdehyde precursor capable of undergoing acid hydrolysis selected from the group consisting of hydroxysulfonates represented by the formula ##STR58##  wherein R 1  and R 2  represent hydrogen, hydroxyl, or a C 1-5  alkyl group; M is an alkali metal, x is an integer from 0 to 10; and     D. at least one second low volatility brightening agent selected from the group consisting of (a) aromatic aldehydes and substituted aromatic aldehydes, with the exception of benzaldehyde;   (b) aromatic ketones or substituted aromatic ketones; and   (c) carboxaldehydes of heterocyclic rings or substituted heterocyclic rings.     
     
     
       31. The plating bath according to claim 25, in which the electrolyte consists of alkane and alkanol sulfonic acids represented by the following two general formulae:   RCH.sub.2 SO.sub.3 H     wherein R represents H or a C 1-6  alkyl group, and     HO--RSO.sub.3 H     wherein R represents a C 1-6  alkylene group.   
     
     
       32. The plating bath according to claim 25, in which the alkane or alkanol sulfonic acid electrolyte is used in concentrations ranging from 2 to 25 percent acid. 
     
     
       33. The plating bath according to claim 25, in which the tin is supplied as stannous alkane sulfonate or stannous alkanol sulfonate: Sn(O 3  SR) 2  or SN(O 3  S--R--OH) 2 , respectively, where total tin metal concentration ranges from about 10 to 100 grams per liter. 
     
     
       34. The plating bath according to claim 25, in which the lead is supplied as plumbous alkane sulfonate or plumbous alkanol sulfonate: Pb(O 3  SR) 2  or Pb(O 3  S--R--OH) 2 , respectively, where total tin metal concentration range is from about 10 to 100 grams per liter and the total lead metal concentration range is from about 0.25 to about 50 grams per liter. 
     
     
       35. The plating bath according to claim 25, in which the defoamer is used in concentrations ranging from about 0.01 to about 30 grams per liter. 
     
     
       36. The plating bath according to claim 25, in which the non-volatile brightening is used in concentrations ranging from about 0.1 to 20 grams per liter. 
     
     
       37. The plating bath according to claim 25, in which the aromatic aldehyde and/or the aromatic ketone and/or the carboxaldehyde substituted hetrocyclic ring are each used in concentrations ranging from about 0.005 to about 0.5 grams per liter. 
     
     
       38. The plating bath according to claim 25, in which the antioxidant is used in concentrations of from about 0.1 to about 0.8 grams per liter. 
     
     
       39. A method for producing a bright electroplate coating of tin or tin-lead on an electroplatable object comprising contacting an electroplatable object with a tin or tin-lead alloy plating bath which comprises: A. a plating bath containing a bath soluble alkane or alkanol sulfonic acid;   B. tin alkane or alkanol sulfonate or both tin and lead alkane or alkanol sulfonate;   C. a brightening agent selected from the group consisting of a non-volatile brighteners selected from the group of i. a substituted dihydropyran represented by the following two formulae: ##STR59##  wherein R 1 , R 2 , R 3 , and R 4  represent hydrogen or a C 1-5  alkyl group; x is an integer from 0 to 5; and/or   ii. a substituted dihydrofuran represented by the formulae: ##STR60##  wherein R 1 , R 2 , R 3  and R 4  represent hydrogen or a C 1-5  alkyl group; and/or   iii. a substituted tetrahydrofuran represented by the formula ##STR61##  wherein R 1 , R 2 , R 3  and R 4  represent hydrogen or a C 1-5  alkyl group; and/or   iv. an acetal of dialdehyde represented by the formula ##STR62##  wherein R 1 , R 2 , R 3 , R 4 , R 5  and R 6  represent hydrogen or a C 1-5  alkyl group; x is an integer form 1 to 10; and/or   v. a hydroxysulfonate represented by the formula ##STR63##  wherein R 1  and R 2   represent hydrogen, hydroxyl, or a C 1-5  alkyl group; M is an alkali metal, x is an integer from 0 to 10;     D. a second low volatility brightening agent selected from the group consisting of (a) aromatic aldehydes and substituted aromatic aldehydes, excluding benzaldehyde; and/or   (b) aromatic ketones or substituted aromatic ketones; and/or   (c) carboxaldehydes of heterocyclic rings or substituted heterocyclic rings; and     E. a surfactant selected from the group consisting of: (a) a nonionic surfactant selected from the group represented by the formula ##STR64##  wherein R 1  and R 2  represent hydrogen or --CH 3  ; R 3 , R 4  and R 5  represent H, a C 1-20  alkyl, benzyl, and/or a styryl group; x and y are integers from 1-30; and/or   (b) a nonionic surfactant that is a block copolymer of ethylene and propylene oxide selected from the group represented by the formula ##STR65##  wherein A represents a halogen, --OH, or --OR, where R is a C 1-15  group; x, y, and z are integers from 1 to 100; and/or   (c) a nonionic surfactant that is a block copolymer of ehtylene and propylene oxide selected from the group represented by the formula ##STR66##  wherein A represents a halogen, --OH, or --OR, where R is a C 1-15  group; x, y, and z are integers from 1 to 100;     F. a non-silicon defoaming agent selected from the group consisting of: (a) a polypropylene oxide or nonionic surfactant from the group represented by the formula ##STR67##  wherein A represents a halogen, --OH, or --OR, where R is a C 1-15  alkyl group; x, y, z are integers from 1 to 100; with the condition that no more than 10% of the compound is polyethylene oxide; and/or   (b) a polypropylene oxide or nonionic surfactant from the group represented by the formula ##STR68##  wherein A represents a halogen, --OH, or --OR, where R is a C 1-15  alkyl group; x, y, z are integers from 1 to 100 with the condition that no more than 10% of the compound is polyethylene oxide; and/or   (c) an aliphatic alcohol, represented by the formula   R-OH        wherein R is a C 5-30  alkyl group; and/or   (d) an ethoxylated alkyl phenol from the group represented by the formula ##STR69##  wherein R 1 , R 2  and R 3  represent hydrogen or C 1-16  alkyl groups with the condition that there is at least one alkyl group; x is an integer from 1-5; and     G. antioxidant selected from the group consisting of 1-phenyl-3-pyrazolidinone, resorcinol, catechol, and hydroguinone sulfonate.   
     
     
       40. The method of claim 39, wherein bath electrolytes are selected from bath soluble alkane or alkanol sulfonic acids. 
     
     
       41. The method of claim 39, wherein the source of tin or tin and lead is alkane or alkanol sulfonate containing each of the metals in the plus two oxidation state. 
     
     
       42. The method of claim 39, wherein the plating bath contains at least one low to moderate foaming surfactant in a concentration range between about 1 and about 15 grams per liter. 
     
     
       43. The method of claim 39, wherein the plating bath contains at least one nonsilicon containing defoamer. 
     
     
       44. The method of claim 39, wherein the plating bath further contains a nonvolatile brightener consisting of a substituted dihydropyran, a substituted dihydrofuran, a substituted tetrahydrofuran, an acetal of a dialdehyde, or a hydrosulfonate of a dialdehyde. 
     
     
       45. The method of claim 39, wherein the plating bath further contains a low volatility brightening agent selected from the group consisting of: (a) aromatic aldehydes and substituted aromatic aldehydes and/or their acid hydrolyzable precursors;   (b) aromatic ketones or substituted aromatic ketones;   (c) carboxaldehydes of heterocyclic rings or substituted heterocyclic rings;   (d) and mixtures thereof.   
     
     
       46. The method of claim 39, wherein the plating bath further contains an antioxidant selected from the group consisting of resorcinol, catechol, hydroquinone sulfonate, and 1-phenyl-3-pyrozolidinone. 
     
     
       47. The method of claim 39, wherein said method yields a semi-bright electroplated finish on the object electroplated thereby. 
     
     
       48. The method of claim 39, wherein said method yields a mirror-bright finish on the object electroplated thereby.